Can experiments select the configurational component of excess entropy?

Area of Science:

• Condensed Matter Physics
• Materials Science
• Physical Chemistry

Background:

• Configurational entropy is a theoretical concept used to explain the structural dynamics and relaxation processes in glass-forming liquids.
• A significant challenge in studying glass-forming liquids is the experimental inaccessibility of configurational entropy.
• Understanding the contribution of structural configurations to the overall entropy is vital for predicting material properties.

Purpose of the Study:

• To introduce a novel experimental procedure for estimating the configurational component of excess entropy in liquids.
• To quantify the contribution of structural relaxation to the excess entropy.
• To validate the proposed method using well-characterized glass-forming liquids.

Main Methods:

• The study combined dynamic and thermodynamic property measurements as functions of temperature and pressure.
• A novel procedure was developed to isolate and quantify the configurational entropy contribution from the total excess entropy.
• The method was applied to three distinct glass-forming liquids: orthoterphenyl, salol, and glycerol.

Main Results:

• The developed method successfully estimated the configurational entropy contribution in the studied liquids.
• Results indicated that the configurational entropy constitutes approximately 70% of the excess entropy across all tested materials.
• This finding provides experimental validation for the significant role of structural configurations in liquid entropy.

Conclusions:

• The introduced experimental procedure offers a viable method for determining the experimentally elusive configurational entropy.
• Configurational entropy is a dominant factor in the excess entropy of the investigated glass-forming liquids.
• This work advances the understanding of liquid dynamics and the glass transition phenomenon.